Molecular torsion springs: alteration of helix curvature in frustrated tertiary folds. Issue 6 (16th January 2023)

• Record Type: Journal Article
• Authors: Menke, Friedericke S.; Mazzier, Daniela; Wicher, Barbara; Allmendinger, Lars; Kauffmann, Brice; Maurizot, Victor; Huc, Ivan
• Is Part Of: Organic & biomolecular chemistry. Volume 21:Issue 6(2023)
• Page Start: 1275
• Page End: 1283
• Publication Date: 2023-01-16
• Subjects: Chemistry, Organic -- Periodicals; Bioorganic chemistry -- Periodicals; Chemistry, Physical organic -- Periodicals; 547
• DOI: 10.1039/d2ob02109a
• Languages: English
• ISSNs: 1477-0520

Abstract

Abstract : Fulfilling stabilizing hydrogen bonds in a synthetic helix–turn–helix structure may concomitantly generate conformational frustration. Abstract : The first abiotic foldamer tertiary structures have been recently reported in the form of aromatic helix–turn–helix motifs based on oligo-quinolinecarboxamides held together by intramolecular hydrogen bonds. Tertiary folds were predicted by computational modelling of the hydrogen-bonding interfaces between helices and later verified by X-ray crystallography. However, the prognosis of how the conformational preference inherent to each helix influences the tertiary structure warranted further investigation. Several new helix–turn–helix sequences were synthesised in which some hydrogen bonds have been removed. Contrary to expectations, this change did not strongly destabilise the tertiary folds. On closer inspection, a new crystal structure revealed that helices adopt their natural curvature when some hydrogen bonds are missing and undergo some spring torsion upon forming the said hydrogen bonds, thus potentially giving rise to a conformational frustration. This phenomenon sheds light on the aggregation behaviour of the helices when they are not linked by a turn unit.